THE Brown Bounce' was in full effect today after Labour comfortably held Glenrothes in a crucial by-election.

In a result that seemed to take even party insiders by surprise, their candidate Lindsay Roy coasted to victory with a majority of 6737 after yesterday's poll.

Although the margin was down a third on that achieved at the 2005 General Election, the win will be seen as a huge personal boost for Gordon Brown.

Just weeks ago, Glenrothes looked set to be the third safe seat' Labour would lose under his leadership, with the poor performance sparking calls for him to quit.

However, since then Mr Brown has been reinvigorated by his handling of the global financial crisis, slashing the Tories' poll lead and seemingly impressing voters in Glenrothes.

The constituency borders the Prime Minister's Kirkcaldy and Cowdenbeath constituency and Mr Brown staked political capital by visiting it twice during the campaign breaking the precedent that premiers stay away from by-elections.

Mr Brown's wife Sarah was also deployed to help bring in support.

As the count began last night, the SNP were expressing confidence that they had achieved the 14.3% swing needed to overturn the 10,664 majority. But the mood soon changed, with one Labour official admitting he was "bewildered" by the turnaround.

Delivering his victory speech, Mr Roy praised the PM, saying: "I pledge my support to the leader of this country, someone who has worked very hard on behalf of all of us, not just in Fife, but in Scotland and the UK during these volatile economic times."

Meanwhile, SNP candidate Peter Grant tried to put a brave face on defeat. "We have seen the SNP vote in this constituency increase by almost 50% on what it was a few years ago," he said.

"That is a magnificent result by any standards, without taking anything away from Labour's achievement."

Labour aides gleefully circulated comments by SNP leader Alex Salmond in the agenda to his party's conference last month, where he said: "The Glasgow East and Glenrothes by-elections put us well on our way to reach our target of 20 MPs at the Westminster election."

Labour's terrible run prior to Glenrothes saw them thrashed in local elections before losing a 7000 majority to the Tories in Crewe and Nantwich in May.

The party's modern-day nadir came in July in Glasgow East, where the SNP achieved an enormous 22.5% swing to overturn a 13,000 majority.

The Glenrothes poll, caused by the death of MP John MacDougall, was seemingly timed to be overshadowed by the US presidential election.

However, in the event the scale of the Labour victory was more than respectable for a Government in the middle of its third term. The number of votes for the party and its share of the vote were actually up on 2005 levels.

Liberal Democrat candidate Harry Wills and Tory Maurice Golden lost their deposits.

Scottish Secretary Jim Murphy said: "The people of Fife have put their faith in Labour again.

"There is an economic storm sweeping the globe. The people yesterday put their faith in Gordon Brown. And it is a real personal tribute to the work that he has been doing.